This invention relates to tree harvesting, and more particularly to a tree harvesting machine attached to a self-propelled vehicle and adapted to cut trees and to stack them in piles.
There are many prior art devices for tree harvesting. A typical prior art device grips the vertical tree and holds it in place, shears or cuts it off, and then rotates and lowers the tree to the ground. A separate processing machine is often used to then delimb the tree. In many prior art devices, the growing tree must be approached from the front for it to be gripped and then cut. This approach is difficult if the desired tree is surrounded by other growing trees. In that case, the growing tree is typically manually cut down with a chain saw and thereafter gripped by the harvester for delimbing and stacking. This procedure is time-consuming because it requires the additional, manual cutting step.
Once the tree has been cut, it is often desirable to stack the tree on a pile with other cut trees. The tree harvesting apparatus typically grabs the tree and carries it to a place for stacking. In typical prior art tree harvesters, the vehicle to which the tree harvester is attached must approach the stack straight on so that the gripped tree can be dropped onto the stack in the straight ahead or forward direction. That is, typical prior art harvesters are not capable of stacking trees where the stack is located to the side of the vehicle. If side stacking is needed, the vehicle itself must be repositioned so that the stack is directly in front of the vehicle. This procedure is time-consuming because the large vehicle is difficult to maneuver for such repositioning. Also, the forest area where the trees are being cut may have inadequate room for the carrier vehicle to easily maneuver into the correct position.
Some prior art tree harvesters also have saw assemblies for cutting down the trees. These saw assemblies typically include a saw bar having a chain interconnected with sprockets on the periphery of the saw bar. Typical prior art saw bars have a rectangular shape which increases the likelihood that the chain will jump off the sprockets, resulting in harvesting downtime.